Motorcycle frame



FIG. 1 is an environmental perspective view of a motorcycle frame showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view with the left side being a mirror image thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken line showing of portions of a motorcycle is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a motorcycle frame, as shown and described. 